If asked what are the differences between a grandfather and his newborn granddaughter, I would reply with the obvious ones: size (the grandfather is larger than his granddaughter), condition of the skin (babies have soft, smooth skin and elders have age spots and wrinkles) and life expectancy. Other visual cues may seem more similar than different. For example, grandfather and granddaughter may both lack hair on their heads or need assistance to move from one place to another. However, both baby and elder are a product of the genes expressed from their genome even if the exact sequence is not identical between them. Because genes are expressed differently over a human’s lifetime, Heyn et al. decided to examine the methylation profile in the genomes of newborns and individuals 89 years old or older. Continue reading “Methylation of Your Genome Decreases as You Age”